This invention relates generally to the use of linear guides and, more specifically, to apparatus and methods for automatically compensating for some misalignment occurring between two linear guides.
In mechanical devices such as machine tools, it is common to have two linear guides supporting a moving axis. To ensure accurate movement, the linear guides should have substantially no clearance or minimal clearance between respective rails and bearings.
When two or more linear guides are employed together, with little or no clearance, then the linear alignment of the two guides needs be very precise. The rails should be both parallel and co-planar level i.e. should be in the same plane.
If the guides are not precisely parallel and level, then unacceptably high loads can be imposed on the guides, which reduces the guide life.
A typical method for configuring two linear guides for controlling one axis is to mount the two guides onto a machined surface against shoulders which control the errors in misalignment due to the machining accuracies of the surface and shoulders.
In applications where two linear recirculating ball bearing block guides are spaced apart and cannot be reasonably connected, the accuracy of alignment of the two guides for parallel and level is around 0.001 inches. In applications where linear guides are mounted independently relative to each other, with no machined items to control their respective positions, linear guides are typically not feasible to use, as the loads generated by misalignment lead to premature failure.
In machine tools, however, linear recirculating ball bearing block guides are often the preferred method of linear guide, due to their smoothness, load carrying capacity, debris protection, and the fact that if damage occurs, replacement parts can simply be bolted into place without the need for any machining of the guide systems.